Beluchenko's p40 is a period40oscillator discovered by Nicolay Beluchenko on March 4, 2009.[1] In terms of its 26cells, it is the smallest known period 40 oscillator. Blocks can be shared: the same block can be hassled with two copies of the oscillator at a displacement of half the period (or other nearby timings). The shared block is hassled with a displacement of one period.